Careers360 Logo
JEE Main 2025 Admit Card Session 2 for BTech Released – Download Hall Ticket at jeemain.nta.nic.in

Evaluation of Definite Integrals by Substitution - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • 29 Questions around this concept.

Solve by difficulty

The solution for x of the equation  \int_{\sqrt{2}}^{x}\; \frac{dt}{t\sqrt{t^{2}-1}}=\frac{\pi }{2}     is

The value of 01x1/2(1x)1/2dx is equal to

limn[1n+n2(n+1)3+n2(n+2)3+...+18n]=

The value of the integral

13((x2)4sin3(x2)+(x+2)2019+1)dx

is

Concepts Covered - 1

Evaluation of Definite Integrals by Substitution

We have already learned to find Indefinite Integration by using the substitution method. But in the case of definite integration, we also need to change the limits of integration 'a' and 'b'. If we substitute x = g(t), then g(t)  must be continuous in the interval [a, b].

Let's look at some examples of how such questions are solved.

Example 1

Compute the integral 0π/2dxa2cos2x+b2sin2x
Let I=x=0x=π/2dxa2cos2x+b2sin2x
Divide numerator and denominator by cos2x
=x=0x=π/2sec2xdxa2+b2tan2x

Put tanx=tsec2xdx=dt
I=t=0t=dta2+b2t2

We find the new limits of integration t=tanxt=0 when x=0 and t= when x=π/2
I=1b20dt(ab)2+t2=1b21a/b[tan1bta]0=1ab[π20]=π2ab

 

 

Study it with Videos

Evaluation of Definite Integrals by Substitution

"Stay in the loop. Receive exam news, study resources, and expert advice!"

Get Answer to all your questions

Back to top